Getting out a hotfix on uniregistry.com right now... Typically our pricing is very competitive, but haven't checked the markup on these. Sorry about the self-promotion. Edit: EAP is live.
I registered our (trademarked) .app through 101domain 2 weeks ago. And I believe GoDaddy also supports Early Access (with better prices).
Confirmed that gandi.net does support it
That must have been a just-missed thing - I checked Gandi just before my post